Preparation of aromatic hydrocarbons



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3,070,638 PREPARATION OF AROMATIC HYDROCARBONS Sterling E. Voltz, Media, Pa., assignor to Sun i] Company, Philadelphia, Pa., a corporation of New Jersey N0 Drawing. Filed July 20, 1960, Ser. No. 44,000 4 Claims. (Cl. 260-668) This invention relates to a method for preparing aromatic hydrocarbons from cyclododecatriene-l,5,9.

It is known that cyclododecatriene-1,5,9 can be prepared by contacting butadiene with a catalyst formed from titanium tetrachloride and diethyl aluminum chloride in a hydrocarbon solvent. This catalyst system produces the trans-trans-cis form of the triene exclusively.-

It is also known that cyclododecatriene-1,5,9 can be prepared by contacting' butadiene with a catalyst system which is aluminurn triethyl together with either chromyl chloride or chromic chloride in a hydrocarbon solvent. The

latter type of catalyst system producesmainly" the transtrans-trans form of the triene but also causes the forma-,

tion of substantial amounts of the trans-trans-cis isomer.

" temperature ranges .vary with the catalyst selected. "Us-1- ing acidic siliceous cracking catalysts a temperature-,of 250400 C. is preferred. With chromia-altunina the pre{' The present invention provides a method of converting either isomeric form of cyclododecatriene-1,5,9 into a variety of aromatic hydrocarbons. The products obtained can include alkyl benzenes, tetralins, indanes, indenes. naphthalenes and acenaphthenes;

According to the invention, cyclododecatriene-1,5,9 is contacted in vapor phaseat'a'temperature in the range'of ZOO-600 C. with a solid granular catalyst, whereby reaction occurs and aromatic hydrocarbons are obtained as Several diiferent types of catalyst can be used product. to effect this reaction. 1 One su1table type comprises the acidic siliceous cracking catalysts, such as silica-alumina,

desired temperature, was fed through'the catalyst bed'at the distribution of aromatic products space velocity in the range of 0.5-3.0 is used. Preferredconditions the "formation of alkyl benzenes can be substantially avoided if desired. Small amounts of gas and coke are formed in the reaction.

The following specific examples illustrate various conditions for carrying out the present proces and show how varieswith changes in catalyst and conditions of operation.

EXAMPLE 'I' Ac ommercial silica-alumina cracking catalyst was used to promote the reaction of cyclododecatriene-l,5,9 at three different temperaturelevels, namely, 300, 400 and 500? C. The catalyst was packed in a continuous fiowreactor and the cyclododecatriene, which had been heated to the about atmospheric pressure and at a space velocity of 2.0.

- The liquidproduct was condensed in-acoldtrap and uncondensible gas was separately collected. Results of analysis of the liquid product by low voltage mass spectrometry are shown in Table I.

Table 1 REACTION OF CYCLODODECAIRIENE-1;5,9,"OVER" SILIOA-ALUMINA CATALYST ,C Liquid product composition, vol. percent I oke Run Reaction Gas make, make, I No. temp,,C weight weight Number-oi Genericiormula percent percent carbon atoms (11) n In-fl Cn n-s n hr-IB Cu In-fl Cn h-u B 400 4.7 2.6 8 1.7 '9 3.7 10 1.1 .c W 1 1--- -07 12 4.5 10.2.. 4.5 is 1.3 1.0 C 500 10.7 3.0 6 1.1

silica-magnesia, silica-zirconia and acid treated clays.

Catalysts which are particularly useful in practicing the invention are chromia-alumina and molybdenum oxide-a alumina. Another suitable type comprises the platinumalrriina actalysts which are widely used in reforming operations. Still another suitable catalyst is cobalt molybdate Suitable space velocities for effecting contact of the cyclododecatriene with any of these catalysts lie in-the range of 0.2-5.0 liquid volumes of cyclododecatriene per The data given in Table I show the percentages of components having from 6 to 15 carbon atoms and having bull? um 9P ta1Yt..Ps ,hQEI.-, M. I...1 l?l .a aaphthalenes. audacenanh respectively- Patented Dec. 25, 1962 The data in Table I show that the silica-alumina catalyst at'300 C. causes substantially complete conversion of the starting triene to aromatics which are mainly tetralins, indanes and indenes. As the temperature is raised, more lower molecular weight aromatics are produced, so that at a temperature of 500 C. roughly 20% of the product is alkyl benzenes. The data indicate, however, that the amount of coke formed is substantially independent of example tend to form less alkyl benzenes and more tetralins, indanes and indenes.

EXAMPLE III Two runs were made at temperatures of 400 and 500 C., respectively, using a commercial chromia-alumina catalyst. Conditions otherwise were as described in Example I. Results are shown in Table III.

Table III REACTION OF CYCLODODECATRIENE-1,5,9 OVER CHROMIA-ALUMINA CATALYST Liquid product composition, vol. percent Coke Run Reaction Gas make, make, No. temp.,C. weight weight Number oi Generic formula percent percent carbon atoms (11) Cn Iu-O Cu In-B Cn m-m Cn Zn-H nHin-ll 1( 1.1 0.6 12 23. 6 35. 7 29.8 7.0 1.1 G... 400' 1.1 1. 4 12 4. 0 s1. 4 1s. 4 14. 0 2. a

the'reaction temperature. The data given in Table III show that chromia-alumina EXAMPLE H is an excellent catalyst for converting cyclododecatriene Two runs were made at 500 C. in the same manner as described in the preceding example but in this case the catalysts used were, respectively, acid activated kaolin and silica-magnesia. Results are shown in Table II.

5 without formation of alkyl benzenes.

At 400 C. (run G) virtually all of the starting material was converted to tetralins, indanes, indenes and naphthalenes. Molybdenum oxide-alumina catalysts function in substantially the same way as chromia-alumina.

Table II REACTION OF CYCLODODECATRIENE-1,5,9 OVER KAOLIN AND SILICA-MAGNESIA CATALYSTS AT 500 C.

Liquid product composition, vol. percent Gas make, Coke make, Run No. Catalyst weight weight Number of Generic formula percent percent carbon atoms (11) n llr-fl n ln-! n In-W n Irr-H nHIn-H I) Kaolin. 6.6 2.7 6 0.7

E; Silica-magnesia 8.1 2.9 7 8 9 10 11 12 13 14 1 Comparison of the results listed in Table II with data from the first example show that the catalytic effects of kaolin and silica-magnesia are substantially similar to silica-aluminum, except that the catalysts of the present using a commercial platinum-alumina reforming catalyst. Table IV shows the results.

Table IV REACTION OF CYGLODODECATRIENE-1,5,9 OVER PLATINUM-ALUMINA CATALYST 00k Liquid product composition, vol. percent 0 Run Reaction Gas make, make, No. temp.,C. weight weight Number of Generic formula percent percent carbon atoms (11) Cn tn-o n Ir! n !nl0 Cn Zn-H Cn ln-H The data of Table IV show that platinum-alumina reforming catalysts act somewhat intennediate of the chromia-alumina catalysts and the catalysts specified in Examples I and II but that the selectivity for forming tetralins, indanes, indenes and naphthalenes is high.

While all of the foregoing runs were made at substantially atmospheric pressure, the process can be practiced, if desired, at elevated pressure, for example, at pressures up to 500 p.s.i.g., and generally similar results will be obtained.

I claim:

1. Method of forming aromatic hydrocarbons which comprises contacting cyclododecatriene-1,5,9 in vapor phase with a catalyst selected from the group consisting of acidic siliceous cracking catalysts, chromia-alumina, molybdenum oxide-alumina, cobalt molybdate and platmum-alumina at a temperature in the range of ZOO-600 C. and at a space velocity of 0.2-5.0 volume liquid per bulk volume catalyst per hour.

2. Method according to claim 1 wherein the catalyst is an acidic siliceous cracking catalyst, the temperature is in the range of 250400 C. and the space velocity is 0.5-3.0.

3. Method according to claim 1 wherein the catalyst is chromia-alumina, the temperature is in the range of 300- 500 C. and the space velocity is 0.5-3.0.

4. Method according to claim 1 wherein the catalyst is platinum-alumina, the temperature is in the range of 300-450 C. and the space velocity is 0.5-3.0.

Pit-ts Nov. 29, 1960 Holmes et a1. Feb. 21, :1961 

1. METHOD OF FORMING AROMATIC HYDROCARBONS WHICH COMPRISES CONTACTING CYCLODODECATRIENE-1,5,9 IN VAPOR PHASE WITH A CATALYST SELECTED FROM THE GROUP CONSISTING OF ACIDIC SILICEOUS CRACKING CATALYSTS, CHROMIA-ALUMINA, MOLYBDENUM OXIDE-ALUMINA, COBALT MOLYBDATE AND PLATINUM-ALUMINA AT A TEMPERATURE IN THE RANGE OF 200-600* C. AND AT A SPACE VELOCITY OF 0.2-5.0 VOLUME LIQUID PER BULK VOLUME CATALYST PER HOUR. 